1. Field of the Invention
This invention relates to a lock arrangement in which a declutching mechanism is provided so that in the locked position rotation of the outer handle does not cause actuation and retraction of the latch.
2. Description of the Prior Art
In many of the prior art lock devices, there is incorporated a clutch mechanism by which the latch may be disengaged by manipulation of the inner handle so that the outer handle may be free to rotate when the clutch is disengaged without retraction of the latch. Such arrangements have not, in many instances, proven to be sufficiently strong enough in their operation to withstand comparatively heavy rotational forces on the outer handle. In particular, when the outer handle is a lever as now often required under various state and federal laws in the United States for handicapped access, the forces can be considerable depending upon the length of the lever.
Examples of such declutching mechanisms are shown, for example, in U.S. Pat. No. 4,920,773 in which a declutching mechanism is utilized in connection with a lever handle lock.
Other examples of the prior art patents are shown in, for example, U.S. Pat. No. 2,634,598. Additionally, other examples of prior art lock arrangements are shown in:
Inventor U.S. Pat. No. Issue Date J. A. Rymer 1,834,223 12/01/31 W. F. Nelson 2,062,598 12/01/36 K. A. Brauning 2,175,791 10/10/39 R. F. Peo 2,197,508 04/16/40 F. K. Heyer 2,672,041 03/16/54 Tornoe et al. 3,718,015 02/27/73 Tornoe et al. 3,856,339 12/24/74 Tranberg et al. 3,881,331 05/96/75 Nagy et al. 3,896,644 07/29/75 Kagoura 3,922,896 12/02/75 Dietrich et al. 4,108,482 08/22/78 Dietrich et al. 4,333,324 06/08/82 Kambic 4,429,556 02/07/84 Foshee 4,437,695 03/20/84 Gater et al. 4,631,944 12/30/86 Martin et al. 4,648,639 03/10/87 Best et al. 4,655,059 04/07/87 Huang et al. 4,660,395 04/28/87 Gater et al. 4,672,829 06/16/87 Lin 5,372,025 12/13/94 No exhaustive search of the prior art has been done.